399 lines
9.8 KiB
C
399 lines
9.8 KiB
C
/*
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* (C) 2012-2013 by Pablo Neira Ayuso <pablo@gnumonks.org>
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* (C) 2012-2013 by On Waves ehf <http://www.on-waves.com>
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* All rights not specifically granted under this license are reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Affero General Public License as published by the
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* Free Software Foundation; either version 3 of the License, or (at your
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* option) any later version.
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*/
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#include <stdio.h> /* for printf */
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#include <string.h> /* for memcpy */
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#include <stdlib.h> /* for abs */
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#include <netinet/in.h>
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#include <osmocom/core/msgb.h>
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#include <osmocom/core/talloc.h>
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#include <osmocom/netif/osmux.h>
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#include <osmocom/netif/rtp.h>
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#include <openbsc/mgcp.h>
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#include <openbsc/mgcp_internal.h>
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#include <openbsc/osmux.h>
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#define OSMUX_PORT 1984
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static struct osmo_fd osmux_fd;
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static LLIST_HEAD(osmux_handle_list);
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struct osmux_handle {
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struct llist_head head;
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struct osmux_in_handle *in;
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};
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static void *osmux;
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static void osmux_deliver(struct msgb *batch_msg, void *data)
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{
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struct in_addr *addr = data;
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struct sockaddr_in out = {
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.sin_family = AF_INET,
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.sin_port = htons(OSMUX_PORT),
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};
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char buf[4096];
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memcpy(&out.sin_addr, addr, sizeof(*addr));
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osmux_snprintf(buf, sizeof(buf), batch_msg);
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LOGP(DMGCP, LOGL_DEBUG, "OSMUX delivering batch to addr=%s: %s\n",
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inet_ntoa(out.sin_addr), buf);
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sendto(osmux_fd.fd, batch_msg->data, batch_msg->len, 0,
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(struct sockaddr *)&out, sizeof(out));
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}
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static struct osmux_in_handle *
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osmux_handle_lookup(struct mgcp_config *cfg, struct in_addr *addr)
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{
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struct osmux_handle *h;
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/* Lookup for existing OSMUX handle for this destination address. */
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llist_for_each_entry(h, &osmux_handle_list, head) {
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if (memcmp(h->in->data, addr, sizeof(struct in_addr)) == 0) {
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LOGP(DMGCP, LOGL_DEBUG, "using existing OSMUX handle "
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"for addr=%s\n",
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inet_ntoa(*addr));
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goto out;
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}
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}
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/* Does not exist, allocate it. */
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h = talloc_zero(osmux, struct osmux_handle);
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if (!h)
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return NULL;
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h->in = talloc_zero(osmux, struct osmux_in_handle);
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if (!h->in) {
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talloc_free(h);
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return NULL;
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}
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h->in->osmux_seq = 0; /* sequence number to start OSmux message from */
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h->in->batch_factor = cfg->osmux_batch;
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h->in->deliver = osmux_deliver;
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osmux_xfrm_input_init(h->in);
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h->in->data = addr;
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llist_add(&h->head, &osmux_handle_list);
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LOGP(DMGCP, LOGL_DEBUG, "creating new OSMUX handle for addr=%s\n",
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inet_ntoa(*addr));
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out:
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return h->in;
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}
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int osmux_xfrm_to_osmux(int type, char *buf, int rc, struct mgcp_endpoint *endp)
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{
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int ret;
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struct msgb *msg;
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struct in_addr *addr;
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struct osmux_in_handle *in;
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msg = msgb_alloc(4096, "RTP");
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if (!msg)
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return 0;
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memcpy(msg->data, buf, rc);
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msgb_put(msg, rc);
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switch(type) {
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case MGCP_DEST_NET:
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addr = &endp->net_end.addr;
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break;
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case MGCP_DEST_BTS:
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addr = &endp->bts_end.addr;
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break;
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default:
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/* Should not ever happen */
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LOGP(DMGCP, LOGL_ERROR, "Bad type %d. Fix your code.\n", type);
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return 0;
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}
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/* Lookup for osmux input handle that munches this RTP frame */
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in = osmux_handle_lookup(endp->cfg, addr);
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if (!in) {
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LOGP(DMGCP, LOGL_ERROR, "No osmux handle, aborting\n");
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return 0;
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}
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LOGP(DMGCP, LOGL_DEBUG, "Osmux uses cid=%u from endpoint=%d (active=%d)\n",
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endp->ci, ENDPOINT_NUMBER(endp), endp->allocated);
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while ((ret = osmux_xfrm_input(in, msg, endp->ci)) > 0) {
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/* batch full, build and deliver it */
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osmux_xfrm_input_deliver(in);
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}
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return 0;
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}
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static struct mgcp_endpoint *
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endpoint_lookup(struct mgcp_config *cfg, int cid,
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struct in_addr *from_addr, int type)
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{
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struct mgcp_endpoint *tmp = NULL;
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int i;
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/* Lookup for the endpoint that corresponds to this port */
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for (i=0; i<cfg->trunk.number_endpoints; i++) {
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struct in_addr *this;
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tmp = &cfg->trunk.endpoints[i];
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if (!tmp->allocated)
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continue;
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switch(type) {
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case MGCP_DEST_NET:
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this = &tmp->net_end.addr;
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break;
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case MGCP_DEST_BTS:
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this = &tmp->bts_end.addr;
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break;
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default:
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/* Should not ever happen */
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LOGP(DMGCP, LOGL_ERROR, "Bad type %d. Fix your code.\n", type);
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return NULL;
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}
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if (tmp->ci == cid && this->s_addr == from_addr->s_addr)
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return tmp;
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}
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LOGP(DMGCP, LOGL_ERROR, "Cannot find endpoint with cid=%d\n!\n", cid);
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return NULL;
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}
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static void scheduled_tx_net_cb(struct msgb *msg, void *data)
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{
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struct mgcp_endpoint *endp = data;
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struct sockaddr_in addr;
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mgcp_send(endp, MGCP_DEST_NET, 1, &addr, (char *)msg->data, msg->len);
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msgb_free(msg);
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}
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static void scheduled_tx_bts_cb(struct msgb *msg, void *data)
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{
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struct mgcp_endpoint *endp = data;
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struct sockaddr_in addr;
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mgcp_send(endp, MGCP_DEST_BTS, 1, &addr, (char *)msg->data, msg->len);
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msgb_free(msg);
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}
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static struct msgb *osmux_recv(struct osmo_fd *ofd, struct sockaddr_in *addr)
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{
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struct msgb *msg;
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socklen_t slen = sizeof(*addr);
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int ret;
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msg = msgb_alloc(4096, "OSMUX");
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if (!msg) {
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LOGP(DMGCP, LOGL_ERROR, "cannot allocate message\n");
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return NULL;
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}
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ret = recvfrom(ofd->fd, msg->data, msg->data_len, 0,
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(struct sockaddr *)addr, &slen);
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if (ret <= 0) {
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msgb_free(msg);
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LOGP(DMGCP, LOGL_ERROR, "cannot receive message\n");
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return NULL;
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}
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msgb_put(msg, ret);
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return msg;
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}
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int osmux_read_from_bsc_nat_cb(struct osmo_fd *ofd, unsigned int what)
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{
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struct msgb *msg;
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struct osmux_hdr *osmuxh;
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struct llist_head list;
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struct sockaddr_in addr;
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struct mgcp_config *cfg = ofd->data;
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char buf[4096];
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msg = osmux_recv(ofd, &addr);
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if (!msg)
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return -1;
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/* not any further processing dummy messages */
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if (msg->data[0] == MGCP_DUMMY_LOAD)
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goto out;
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osmux_snprintf(buf, sizeof(buf), msg);
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LOGP(DMGCP, LOGL_DEBUG, "received OSMUX message from "
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"BSC NAT (len=%d) %s\n", msg->len, buf);
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while((osmuxh = osmux_xfrm_output_pull(msg)) != NULL) {
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struct mgcp_endpoint *endp;
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/* Yes, we use MGCP_DEST_NET to locate the origin */
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endp = endpoint_lookup(cfg, osmuxh->circuit_id,
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&addr.sin_addr, MGCP_DEST_NET);
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if (!endp) {
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LOGP(DMGCP, LOGL_ERROR,
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"Cannot find an endpoint for circuit_id=%d\n",
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osmuxh->circuit_id);
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goto out;
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}
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LOGP(DMGCP, LOGL_DEBUG,
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"sending extracted RTP from OSMUX to BSC via endpoint=%u "
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"(allocated=%d)\n", ENDPOINT_NUMBER(endp), endp->allocated);
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osmux_xfrm_output(osmuxh, &endp->osmux_out, &list);
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osmux_tx_sched(&list, scheduled_tx_bts_cb, endp);
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}
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out:
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msgb_free(msg);
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return 0;
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}
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int osmux_read_from_bsc_cb(struct osmo_fd *ofd, unsigned int what)
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{
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struct msgb *msg;
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struct osmux_hdr *osmuxh;
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struct llist_head list;
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struct sockaddr_in addr;
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struct mgcp_config *cfg = ofd->data;
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char buf[4096];
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msg = osmux_recv(ofd, &addr);
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if (!msg)
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return -1;
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/* not any further processing dummy messages */
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if (msg->data[0] == MGCP_DUMMY_LOAD)
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goto out;
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osmux_snprintf(buf, sizeof(buf), msg);
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LOGP(DMGCP, LOGL_DEBUG, "received OSMUX message "
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"from BSC (len=%d) %s\n", msg->len, buf);
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while((osmuxh = osmux_xfrm_output_pull(msg)) != NULL) {
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struct mgcp_endpoint *endp;
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/* Yes, we use MGCP_DEST_BTS to locate the origin */
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endp = endpoint_lookup(cfg, osmuxh->circuit_id,
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&addr.sin_addr, MGCP_DEST_BTS);
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if (!endp) {
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LOGP(DMGCP, LOGL_ERROR,
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"Cannot find an endpoint for circuit_id=%d\n",
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osmuxh->circuit_id);
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goto out;
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}
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LOGP(DMGCP, LOGL_DEBUG,
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"sending extracted RTP from OSMUX to MSC via endpoint=%u "
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"(allocated=%d)\n", ENDPOINT_NUMBER(endp), endp->allocated);
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osmux_xfrm_output(osmuxh, &endp->osmux_out, &list);
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osmux_tx_sched(&list, scheduled_tx_net_cb, endp);
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}
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out:
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msgb_free(msg);
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return 0;
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}
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int osmux_init(int role, struct mgcp_config *cfg)
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{
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int ret;
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switch(role) {
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case OSMUX_ROLE_BSC:
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osmux_fd.cb = osmux_read_from_bsc_nat_cb;
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break;
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case OSMUX_ROLE_BSC_NAT:
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osmux_fd.cb = osmux_read_from_bsc_cb;
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break;
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default:
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LOGP(DMGCP, LOGL_ERROR, "wrong role for OSMUX\n");
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return -1;
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}
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osmux_fd.data = cfg;
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ret = mgcp_create_bind("0.0.0.0", &osmux_fd, OSMUX_PORT);
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if (ret < 0) {
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LOGP(DMGCP, LOGL_ERROR, "cannot bind OSMUX socket\n");
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return ret;
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}
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osmux_fd.when |= BSC_FD_READ;
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ret = osmo_fd_register(&osmux_fd);
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if (ret < 0) {
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LOGP(DMGCP, LOGL_ERROR, "cannot register OSMUX socket\n");
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return ret;
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}
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cfg->osmux_init = 1;
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return 0;
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}
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int osmux_enable_endpoint(struct mgcp_endpoint *endp, int role)
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{
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/* If osmux is enabled, initialize the output handler. This handler is
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* used to reconstruct the RTP flow from osmux. The RTP SSRC is
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* allocated based on the circuit ID (endp->ci), which is unique in the
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* local scope to the BSC/BSC-NAT. We use it to divide the RTP SSRC
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* space (2^32) by the 256 possible circuit IDs, then randomly select
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* one value from that window. Thus, we have no chance to have
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* overlapping RTP SSRC traveling to the BTSes behind the BSC,
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* similarly, for flows traveling to the MSC.
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*/
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static const uint32_t rtp_ssrc_winlen = UINT32_MAX / 256;
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if (!endp->cfg->osmux_init) {
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if (osmux_init(role, endp->cfg) < 0) {
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LOGP(DMGCP, LOGL_ERROR, "Cannot init OSMUX\n");
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return -1;
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}
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LOGP(DMGCP, LOGL_NOTICE, "OSMUX requested, ENABLING.\n");
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}
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osmux_xfrm_output_init(&endp->osmux_out,
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(endp->ci * rtp_ssrc_winlen) +
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(random() % rtp_ssrc_winlen));
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switch (endp->cfg->role) {
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case MGCP_BSC_NAT:
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endp->type = MGCP_OSMUX_BSC_NAT;
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break;
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case MGCP_BSC:
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endp->type = MGCP_OSMUX_BSC;
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break;
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}
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endp->osmux = 1;
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return 0;
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}
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/* We don't need to send the dummy load for osmux so often as another endpoint
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* may have already punched the hole in the firewall. This approach is simple
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* though.
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*/
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int osmux_send_dummy(struct mgcp_endpoint *endp)
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{
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static char buf[] = { MGCP_DUMMY_LOAD };
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LOGP(DMGCP, LOGL_DEBUG, "sending OSMUX dummy load to %s\n",
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inet_ntoa(endp->net_end.addr));
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return mgcp_udp_send(osmux_fd.fd, &endp->net_end.addr,
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htons(OSMUX_PORT), buf, 1);
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}
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